Furnace roof construction

ABSTRACT

At least one element is hinged to a retaining ring that supports the roof of an electric arc furnace, and is movable from an operative position over the roof to an inoperative position free of the roof. The individual bricks comprising the roof can be held up and/or held down by the hinged element when such is in its operative position, and means are provided for removably fixing the hinged element in its operative position.

ilte States aiem [191 [111 3,756,1 2

Brereton et a1. Sept. 4, 1973 [54] FURNACE ROOF CONSTRUCTION 3,367,2922/1968 Woodruff et al. 110/99 2,551,941 5/1951 Greene 110/99 [75]Invemms: Ray'mnd memo; 1 773 359 8/1930 Hilliard 263/46 Wilkinson Lythe,both of Worksop, land FOREIGN PATENTS OR APPLICATIONS [73] Assignee:Steetly (Mfg) Ltd., 1,205,692 9/1970 Great Britain 263/46Nottinghamshire, England [22] Filed: Dec. 17, 1971 Primary ExaminerJohnJ. Camby pp No: 209,315 Assistant ExammerHenry C. Yuen Att0rney.iesse B.Grove, Jr.

[30] Foreign Application Priority Data Dec. 22, 1970 Great Britain60,863/70 1 ABSTRACT At least one element is hinged to a retaining ringthat [52] US. Cl 110/99, 13/35, 45322/76429, Supports the roof Ofanelectric arc furnace and is [51] Int Cl F23m 5/02 able from an operativeposition over the roof to an in- [58] Fieid 6 263/46 operative positionfree of the roof. The individual 52/749 bricks comprising the roof canbe held up and/or held down by the hinged element when such is in itsoperative position, and means are provided for removably [56] ReferencesC'ted fixing the hinged element in its operative position.

UNITED STATES PATENTS 3,448,703 6/1969 Hansen et al 110/99 7 Claims, 6Drawing Figures 9 7 I L\i K 4 PATENTEDSEP 4 um SHEEI 1 OF 4 PATENTED SEP4 I975 SHEET 2 OF 4 PATENTED SEP 4 I975 SHEEI 3 UF 4 roofs.

Electric arc furnace roofs are generally dome-shaped and theconstruction of such roofs is usually accomplished by building up theroof within a retaining ring upon a former remote from the furnace.Installation of the roof and its associated retaining ring is achievedby lifiting the roof and ring bodily onto the electric arc furnace as aunit.

If certain types of refractory bricks e.g., basic bricks are employedfor the roof, it may be necessary to use a superstructure acting both tosupport the roof and to prevent the roof bulging upwards during servicea socalled hold-up hold-down system. The superstructure providessupport, or hold-up, by suspending some or all of the bricks 'of theroof therefrom; it prevents bulging upwards of the roof during servicei.e., it provides holddown, by contact between the superstructure andthe upper surface of some or all of the bricks. The superstructure isattached to the furnace roof and ring while they are on the former. Itis therefore necessary to build the roof within the ring on the formerand then, as a subsequent operation, to lift on the integralsuperstructure and attach the bricks on the roof to the superstructureby means of an appropriate attachment.

When a roof built of refractory bricks is to be repaired the removal ofdamaged bricks and their replacement by new bricks is considerablycomplicated by the presence of the superstructure. Overall, therefore,the presence of the superstructure is a problem during repair orreplacement of the roof.

It has now been found that the replacement and repair of brick roofs forelectric arc furnaces, where such roofs have associated superstructuresperforming holdup and/or hold-down functions, are appreciablyfacilitated if the superstructure is constructed as a number of elementsadapted to be independently rotatable about peripherally located hinges.

According to the present invention there is provided a superstructurefor an electric arc furnace roof adapted to hold-up and/or hold-downpart of said roof, which superstructure is substantially annular or partannular in plan view and comprises one or more elements independentlyhinged to a roof retaining ring.

As well as being useful for dome-shaped roofs, such a superstructure canbe used in connection with electric arc furnace roofs which aresubstantially flat in elevation.

Appropriately each element comprises at least two substantiallyconcentric arc-shaped members connected by one or more transversemembers. Preferably transverse members of the element are hinged at theretaining ring but it is possible for the peripheral arcshaped member tobe so hinged instead. Preferably any arc-shaped member has an underlyingrelationship to any shorter arc-shaped members. The arc-shaped membersmay be adapted to hold-up and/or hold-down the brickwork of the roof.

In one aspect of the invention, bricks which are held down by arc-shapedmembers are not held-up. Preferably alternate rings of bricks are helddown by arcshaped members, the remaining rings of bricks whichthemselves are not held down being suspended from some or all of thearc-shaped members.

In another aspect of the invention each of the bricks in pairs ofadjacent rings of bricks are subject to holddown, preferably by a commonarc-shaped member. Desirably the arc-shaped member is also adapted tohold-up the same pair of adjacent rings of bricks. These pairs of ringsmay adjoin a similarly collocated pair or pairs of rings, or may adjoinrings of bricks subject to either hold-up only or hold-down only orneither holdup nor hold-down.

It is to be understood that the invention further provides an electricarc furnace wherein part of the roof is held-up and/or held-down by asuperstructure as hereinbefore described.

The invention will now be illustrated by way of example, with referenceto the accompanying drawings in which:

FIG. 1 is a section on the line I l of the view in plan of the roof andsuperstructure shown in FIG. 2,

FIG. 2 is a view in plan of one embodiment of an electric arc furnaceroof and its associated superstructure,

FIGS. 3, 4 and 5 are diagrammatic illustrations of certain methods ofhold-up/hold-down used for the roof, and

FIG. 6 is a view in plan of another embodiment of an electric arcfurnace roof and its associated superstructure.

Referring to FIGS. 1 and 2, there is illustrated a roof indicatedgenerally by 1 and superstructure therefor indicated generally by 2.

Roof 1 comprises a series of bricks 3 arranged in concentric rings toform a substantially dome-shaped configuration resting on retaining roofring 4. Alternate rings of these bricks are provided with suspensiontabs 5. The roof 1 is provided with electrode ports 12. The roof may ormay not be self-supporting and may or may not be arched.

The superstructure 2 consists of a plurality of hinged elements 6 whichtogether in the hinged inwards position, form an annular frameworkadapted to hold-up and hold-down the underlying brickwork. Each element6 consists of a series of steel arc-shaped members 7 adapted to overliealternate rings of bricks, the arcshaped members being joined to and bytransverse members 8 which lie radially to the centre of the furaceroof. The transverse members 8 are provided with hinges 9 at their outerends which connect the transverse members with a circular support 10attached to or integral with the retaining roof ring 4.

During construction of a new refractory roof on a former the elements 6are folded outwards. When con struction of the roof is completed theelements are folded inwards, each element 6 being locked by means ofbolts 11 or other fastening devices to its adjoining elements. Thebricks are then attached to the superstructure as necessary. When it isrequired to repair part of the furnace roof, the necessary number ofelements are folded outwards (in FIG. 2 one such element is shown in thefolded outwards position) after severing the suspension between thebricks and the elements. The worn bricks can then be removed andreplaced without any interference from the hold-up/hold-downsuperstructure. When the repair has been effected the outwardly foldedelements 6 can be returned to their inwardly folded position, locked andthe bricks attached to the element by the suspension means.

Some of the various methods which can be used to hold-up/hold-down thebricks are illustrated in FIGS. 3-5.

Referring to FIG. 3 alternate rings of bricks 20 are provided with loops2i. Hook 22 is attached to the loop of one brick, passed over arc-shapedmember 23 and attached to the loop of a brick in the next but one ringof bricks. Alternatively separate hooks can be used to suspend bricksfrom either of the adjacent arc-shaped members. The arc-shaped member 23is located above the intervening ring of bricks and serves to preventany upward movement of this ring.

Referring to FIG. 4, the rings of bricks can be considered in triplets,one ring 24 of which is located below a hold-down arc-shaped member 25and two rings 26 and 27 of which are located below an arc-shaped member28. These latter two rings are provided with loops 29 and 30 which areattached to a hook 31 which passes over members 28 thereby suspendingthe bricks. Alternatively separate hooks can be used to suspend bricksfrom either of the adjacent arc-shaped members. All three rings in thisarrangement are subject to holddown but only two rings are subject tohold-up. The

outermost rings are not subject to hold-up or holddown.

Referring to FIG. 5, all but the outermost rings of bricks are providedwith loops, typical being 32 and 33. Considering the rings in pairs itis to be noted that each pair of rings such as 34 and 35 are locatedbelow an arc-shaped member such as 36. Loops 32 and 33 are attached to ahook 37 which passes over arc-shaped member 36 thereby suspending therings of bricks. Equally, member 36 prevents any excessive rise of theserings of bricks, consequently all the rings of bricks in this embodimentare held-up and held-down.

In any of the embodiments illustrated in FIGS. 3, 4 and 5, it is notnecessary that every brick in any given ring should be suspended and itis possible, for instance, that only alternate bricks in any given ringare suspended. Also in FIGS. 3, 4 and the outer two rings of bricks maybe subject to hold-up and/or hold-down although this is not illustratedas being so.

Referring to FIG. 6 of the drawings, there is illustrated an embodimentof the invention wherein, instead of a superstructure substantiallyannular in plan view as illustrated in FIG. 1, the superstructure 40 ispart annular in plan view and consists of one hinged element 41,attached by fasteners 42 to a centrally located support member 43.Support member 43 consists of three arcshaped members 44, 45 and 46connected to a retaining ring 47 by means of radial supports 48.

Naturally more than one such element 41 may be provided if conditionsdemand it, these elements being located where required.

We claim:

1. In an electric arc furnace, a roof comprised of a plurality of bricksarranged in a pattern, and a superstructure adapted for holding upand/or holding down at least a part of said bricks, said furnaceincluding a roof retaining ring upon which the outer, lower portion ofsaid roof rests, and said superstructure including: at least onesuperstructure element hinged at one end thereof to said retaining ring,whereby said element is pivotally movable from an operative positionlying over said roof, to an inoperative position wherein said element isfree of said roof to provide access to bricks lying thereunder when saidelement is in its operative position, said element when in saidoperative position having means for holding up and/or holding down atleast some of the bricks lying thereunder; and releasable meansengageable with said element, and operable for fixing said element insaid operative position.

2. In an electric arc furnace as recited in claim 1, wherein saidelement comprises: at least two spaced, substantially concentricarc-shaped members, connected by at least one transverse member, saidtransverse member being hinged at its outer end to said retaining ring.

3. In an electric arc furnace as recited in claim 2, wherein said bricksare arranged in concentric rings to form said roof, the bricks in atleast some of said rings underlying said element when said element is insaid operative position thereof being suspended from said arc-shapedmembers of said element.

4. In an electric arc furnace as recited in claim 3, wherein the bricksin others of said rings are held down by said arc-shaped members.

5. In an electric arc furance as recited in claim 2, wherein said bricksare arranged in concentric rings to form said roof, the bricks in atleast some of said rings underlying said element when said element is insaid operative position thereof being held down by said arcshapedmembers of said element.

6. In an electric arc furnace as recited in claim 1, wherein a pluralityof said elements are employed, said elements being arc shaped, and whentaken together in their operative positions forming an annular arraydisposed over said roof, and said means for fixing said elements intheir operative positions comprising removable fasteners interconnectingadjacent portions of said elements near the inner ends thereof.

7. In an electric arc furnace as recited in claim 1, wherein said meansfor fixing said element in its operative position includes: a structuralmember supported over the central portion of said roof; and removablefastener means adapted to secure the inner end of said element to saidsupported structural member.

1. In an electric arc furnace, a roof comprised of a plurality of bricksarranged in a pattern, and a superstructure adapted for holding upand/or holding down at least a part of said bricks, said furnaceincluding a roof retaining ring upon which the outer, lower portion ofsaid roof rests, and said superstructure including: at least onesuperstructure element hinged at one end thereof to said retaining ring,whereby said element is pivotally movable from an operative positionlying over said roof, to an inoperative position wherein said element isfree of said roof to provide access to bricks lying thereunder when saidelement is in its operative position, said element when in saidoperative position having means for holding up and/or holding down atleast some of the bricks lying thereunder; and releasable meansengageable with said element, and operable for fixing said element insaid operative position.
 2. In an electric arc furnace as recited inclaim 1, wherein said element comprises: at least two spaced,substantially concentric arc-shaped members, connected by at least onetransverse member, said transverse member being hinged at its outer endto said retaining ring.
 3. In an electric arc furnace as recited inclaim 2, wherein said bricks are arranged in concentric rings to formsaid roof, the bricks in at least some of said rings underlying saidelement when said element is in said operative position thereof beingsuspended from said arc-shaped members of said element.
 4. In anelectric arc furnace as recited in claim 3, wherein the bricks in othersof said rings are held down by said arc-shaped members.
 5. In anelectric arc furance as rEcited in claim 2, wherein said bricks arearranged in concentric rings to form said roof, the bricks in at leastsome of said rings underlying said element when said element is in saidoperative position thereof being held down by said arc-shaped members ofsaid element.
 6. In an electric arc furnace as recited in claim 1,wherein a plurality of said elements are employed, said elements beingarc shaped, and when taken together in their operative positions formingan annular array disposed over said roof, and said means for fixing saidelements in their operative positions comprising removable fastenersinterconnecting adjacent portions of said elements near the inner endsthereof.
 7. In an electric arc furnace as recited in claim 1, whereinsaid means for fixing said element in its operative position includes: astructural member supported over the central portion of said roof; andremovable fastener means adapted to secure the inner end of said elementto said supported structural member.